Fluid to fluid heat exchanger



May 19, 1953 G. B. R. FEILDEN ETAL. 2,639,125

FLUID TO FLUID HEAT EXCHANGER Filed April 10, 1950 4 5 Sheets-Sheet lffQ a. a. e. Fmoav 1 Tron/Er;

y 1953 s. B. R. FEILDEN EI'AL 2,639,125

' FLUID TO FLUID HEAT EXCHANGER Filed April 10, 1950 '5 Sheets-Sheet 2 y1953 G. B. R. FEILDEN EI'AL 2,639,125

FLUID TO FLUID HEAT EXCHANGER Filed April 10, 1950 5 Sheets-Sheet 3wriwan! 1 rrausr:

y 1953 s. B. R. FE|LDEN ETA1 2,639,125

FLUID TO FLUID HEAT EXCHANGER Filed April 10, 1950 5 Sheets-Sheet 4 e}-5 1 2 I o o o o 0 INDIA/[73' M y 9, 1953 G. B. R. FEILDEN arm. 2,639,125FLUID To "FLUID HEAT EXCHANGER v 5 Sheets-Sheet 5 Filed April 10, 1950Mil/70E;

a. 5.2. FE/LDEN Patented May 19, 1953 UNITED STATES PATENT OFF l-CEFLUID TO FLUID HEAT EXCHANGER Geofirey Bertram Robert "Feilden, Lincoln,and

Raymond Ernest Wigg, Ealing 'Common, London, England, assignors toRuston & Honnshy Limited, Lincoln, England, a British companyApplication April 10, 1950, Seria'LLNo. 155,032 In Great Britain April14, 1949 7 Claims. I

This invention relates to heat exchangers for transferring heat from.one moving body of fluid to another, without admixture and preferablyrecuperatively by counterflow of the fluids in their respectivepassages. More particularly, the invention refers to tubularheat-exchangers in which one fluid is passed through :a number ofparallel tubes enclosed in a casing or casings through which the otherfluid circulates in contact with the outer surfaces of the tubes.

The invention is applicable to heat-exchangers for incorporation ingas-turbine power-plants for utilising otherwise Waste exhaust-"heat toheat the compressed charge before combustion, thereby improving thethermal efficiency of the cycle. However, the improvements comprised inthe present invention are not confined "to .this particular applicationbut may find application in heat-exchangers for other purposes, nor arethey confined to heat-exchangers in which both the fluids participatingin the "heat-transfer are gaseous, but may find application inheatexchangers in which one or both of the fluids are liquid or inevaporators or condensers in which at least one of the fluids changesfrom theliquid to the vapour phase or vice versa.

In a large tubular heat-exchanger having a great number of tubes, acuteproblems are set by differential expansion effects and from this aspectlarge mono-bloc structures present great constructional difficulties.Such structures also present difiicult problems in connection withassembly and maintenance-including cleaning, repair and replacement ofcomponents-end their size usually prohibits any possibility ofrigtesting for checking performance.

The solution of these problems and others as may hereinafter be discusedforms the object of the present invention which makes use of amulti-bloc type of construction in which the individual tube-blocks arereduced to a manageable size, are mounted so that they can expanddifierentially without imposing stresses on their mountings or on eachother and can each be easily removed and i e-assembled withoutinterference with the other tube blocks for cleaning, repair, testing orreplacement. Reliable indications of the performance of the wholeheatexchanger can be obtained from rig-tests carried out on a singletube-block.

A tubular heat-exchanger according to this invention is primarilycharacterised by a number of independent parallel blocks of tubes, ineach of which the tubes are fixed at each end in a header plate, that atone end being secured to a "2 collector member over an opening therein,the joint between the *header-plateand "the collector member beingfluid-tight, and that at theother endbeing provided with a funnel-shapedtubular extensionor cowl, which is supported in anopening inanother=colledtor member by means of a fluid-tight expansion joint; andeach block of tubes is encased for a considerable part of its length ina closely fitting casing leaving the tubes exposed at both ends, "the"fluid which circulates in contact with the outer surfaces of the tubesbeing compelled to pass through these tubebloc'k casings by a bulkheadsubdividing the interior of the external casing of 'the exchanger intotwo compartments and having openings receiving'thc tubebl'ock casings,the joints between the bulkhead openings and tube-block casings beingsealed any convenient manner. The arrangement is such that one fluid ispassed through the tubes from thecollector having the sliding glands tothe other in which the tube-blocks are located (or in the reversedirection), while the other fluid, admitted into the compartment of theouter casing on one-side of "the "bulkhead, circulates through thespaces between the tubes within "the casings of the individualtube-blocks in theopposite direction to that in which the firstmentioned -fluid circulates within the tubes and emerges into thecompartment of the outer casing on the opposite side of the bulkhead,whence it is exhausted.

'In a preferred embodiment of the invention the tube-blocks are disposedhorizontally and the casings of each individual tube-block is providedwith longitudinal horizontal flanges, preferably at the 'top, wherebythe tube-block is supported on rollers, preferably located at or neareach end of the tube-block casing and optionally at an intermediatepoint or points as well, the rollers being mounted on frames 'or bracketstructures, secured to the outer casing of the exchanger or to thetransverse bulkhead.

In a preferred form of construction the collector members are subdividedvertically, each branch being connected to a bank of verticallysuperposed tube-blocks, and the several collector branches beinginterconnected by an integral common header member at the top. Further,the casings .of the individual tube-blocks are flanged near one end andthese flanges abut on the margins of the openings in the bulkhead andcarry .stifiening brackets extending normally from the flanges andhaving holes through which studs projecting from the bulkhead pass tore- =ceive nuts by which the brackets and flanges are clamped to thebulkhead to secure the blockcasings thereto and provide an effectiveseal. These nuts are extended beyond the end of the studs to receivethreaded tie-rods which pass through holes in lugs secured to thebranches of the collector member at that end of the tubeblock assemblyto receive clamping nuts which carry the end loads on the collectormember due to the internal fluid pressure in the tube-blocks. Thetensile loads imposed on the tie-rods by the clamping nuts aretransmitted back through the extended nuts and studs to the bulk-head,and are ultimately counteracted by the equal and opposite end loads, dueto the internal fluid pressure, acting on the collector member at theother end of the tube-blocks, these last-mentioned end loads beingtransmitted back to the bulkhead through connections of the lattercollector member to the outer casing, the tube-blocks themselves beingconnected to the last-mentioned collector member by expansion joints.

The compartment of the outer casing containing the inlet for the fluidwhich circulates round the outside of the tubes is made of largecapacity to ensure low fluid velocity therein and even distribution ofthe fluid to the several tubeblocks and the bulkhead may be set backsome distance beyond the entry ends of the tube-block casings from theend wall of this compartment.

The fluid inlet or outlet of each collector memher is brought outthrough the wall of the outer casing through any convenient type ofseal.

The tube-blocks are preferably of rectangular cross-section enablingthem to be compactly arranged with small clearances between them; andare preferably similar, so that they are interchangeable.

Any one or more of the tube-blocks can be removed and replaced byremoving the (detachable) end wall of the outer casing, the clampingnuts, tie-rods and extended nuts, and disconnecting the collector memberand withdrawing it, thus enabling the tube-blocks to be slid out, andthis is facilitated by the roller method of support. When a tube-blockhas been slid out a certain distance, a traveling slinging tacklesuspended on a gantry extending longitudinally from a position next thedetachable end Wall of the outer casing and located above the level ofthe tube-blocks can be used to support the overhung end of the blockwhile it is being further withdrawn, the slinging tackle comprising ayoke carrying a pair of rollers correctly spaced for slipping under theflanges of the tube-block casings.

It will be seen that each tube-block can expand lengthwise independentlyof the others, when the exchanger is in use, and that no racking strainsare imposed on the collector members or the outer casing. Further, thefluid circulating outside the tubes is confined by the tubeblock casingsto paths in close contact with the tubes throughout the greater part oftheir length.

A further object of the invention is an improved form of flexible jointwhich may be used for the fluid-inlet connection of the outer casing ofa heat-exchanger as described above.

In our improved flexible joint, the mating openings are provided withmutually facing metal flanges which are joined by a short flexiblesleeve of asbestos-base fabric or like material clamped at its edges tothe flanges by means of metal clamping strips. The asbestos may berendered impermeable by any suitable treatment. The clamping strips maybe secured by bolts passing through the flanges and the margins. of theas:

4 bestos fabric sleeve, which may be made from a strip of the fabricwith a sewn, stapled or riveted seam.

If the openings are rectangular or of any other shape having corners, aprotective angle piece of sheet metal may be inserted at each cornerbetween the fabric sleeve and the ends of the clamping strips, which maybe bent outwards and bolted together.

A specific embodiment of the invention is illustrated in theaccompanying drawings by way of example only and without impliedlimitations of the scope of the invention, which is defined in theappended claims.

In the drawings,

Figure l is a perspective view, partly broken away, of a heat-exchanger;

Figure 2 is a view of the same in side elevation partly broken away;

Figure 2a is a sectioned enlargement of the part of Figure 2 ringed witha dotted line;

Figure 3 is a view in end elevation of the intake collector member ofthe internal fluid-circulating system of the heat-exchanger;

Figure 4 is a plan view of the discharge collector assembly of theinternal fluid-circulating system with the top wall removed;

Figure 5 is a detail view in end elevation of the flexible jointconnecting the inlet opening of the heat-exchanger casing with an inlettrunk;

Figure 6 is a view in section on the line 6-6 of Figure 5;

Figure 7 is a View in section on the line 1-1 of Figure 6;

Figure 8 is a view in side elevation illustrating the arrangements forextracting the tube-blocks from the heat-exchanger.

The heat-exchanger comprises a generally rectangular outer casing l0having an internal transverse bulkhead I I, in which are rectangularopenings [2. The interior of the outer casing is thereby divided intotwo compartments, of which the smaller, lying to the right of thebulkhead in Figure 1, has a rectangular inlet opening l3 at the top, theleft-hand end of the outer casing H! (as seen in Figures 1 and 2) beingopen to an exhaust collector (not shown).

Within the outer casing are disposed a number of similar,rectangular-section tube-blocks I4, disposed longitudinally of the outercasing and closely spaced. Each tube-block comprises an open-endedrectangular casing l5, which passes through and fits closely into one ofthe openings I2 of the bulkhead and encases a bundle of closely spacedparallel tubes [6. The latter extend beyond the casing l5 and areexposed at both ends of the tube-block. The ends of the tubes l6 exposedin the compartment of the outer casing to the right of the bulkhead I lin Figure 1 are secured in a header plate 11, the opposite ends of thetubes being secured in a header plate [8, the edges of which are securedin a tubular cowl IS. The fluid-conveying connections of the tube-blockscomprise an intake collector member 20 communicating with the cowls l9and a discharge collector assembly comprising thrce tubular collectors2! communicating with the tubeblocks l4 through the header plates 1.

The collectors 2! are disposed vertically and each communicates with abank of vertically superposed tube-blocks. Each collector has a numberof short branches 22 of rectangular cross-section corresponding in sizand position to the tube-blocks and terminating in openings over whichthe header plates I1 flt. Each header plate I! has a marginal flange 23,which fits over the of the corresponding brand-1:22 ,1 the. jointbeingmade fluid tighti by suitablev packing, and is:- secured to thecollector 2 t by tie bolts Zfiwhich are inserted through apertured'brackets. cxtending from the collector and'carry clamps 2-6 engagingbehindthe marginal flange-23;

The. discharge collectcr assembly also includes a header comprisingthree-elbows idsecurcda to the collectors 2 I, two outlet. pipes 23!forming continuation-s of: the" outer elbows 2:8'and branch pipes 36connecting the: central elbow 28 withthe outlets. 29:, which are led outofthe outer casing I-u-throughfluid-tight glands M The intake. collectormember M comprises three vertical. blind-ended tubes 32 havingcpen-ingsprovided. with skirts 33. which receive the open ends of thecowls l9 together with an integral header of doubleyolrexformcomprisingtwo intake elbows 34- having branches 35, 35,. of which branches 35con-imunicate with the outer'two collector tubes 32 and branches 36 withthe central collector tube 32'. Branches 35 fidextend through a plate3-? which is welded to the branches allroundthe margins oi theopeningsthrough which'thebranches pass; and this plate forms adetachable part of. the top wall. of the i3,- being, secured in anyconvenient way. The lower ends of the collector tubes 32 are providedwith dowels 38 which. are: received in sockets 5i onthe. base-of theoutercasing Hi. The coilector' member 20 is thus positively located bythe plate ill and dowels 38. The elbows 28 and 3d of the collectorassembly 2|, 2? and the collector member 20 are provided. internallywith flow-straightening cascades 5T.

Expansion joints are provided between the ccwls N! of the tube-blocksIll the sl s 3-3 of the openings in-the collector-tubes 3 2' of thecollector member 20'. The sklrts-33 cylindrical and the cowls [9'terminate in cyli a1 portions 58, which flt-sli'd ingly' in the shirts33 and are provided with circumferential grooves holding split springsealing-rings- 59.

The upper wall of each tube-block casing i5 is extended laterally toform longitudinal horizontal flanges 39; which are accommodated in slots49 formed in the bulkhead openings l2, and by which the tube-blocks Mare supported on rollers 4! mounted on bracket structures it secured tothe bulkhead I l and to the inner faces of the walls of the outer casingI0.

The tube-block casings l5 also have collar-like flanges 43, which abuton the margins of the bulkhead openings l2, the joints being suitablypacked to render them fluid-tight. The flanges 43 are stifiened bygusset plates 44 and carry stirrup brackets d5 extending normally to theplane of the flanges and away from the bulkhead H. Studs 46 secured tothe bulkhead extend through holes in the brackets 45 and carry clampingnuts 4! by which the tube-block casings 15 are secured to the bulkhead.

The nuts 4'! are extended to receive threaded tie-rods 4B which passthrough apertured lugs 59 extending from the collectors 2! and carryabutment nuts 50. Internal fluid pressure in the tube-blocks exertsforces on the collectors 2i tending to move them away from the bulkheadl l and these forces are unresisted by the tubes l6 which are free toslide in the tube-block casings H3. The lugs 49, abutment nuts 50, ties4B, nuts 4i and studs 46 transmit these loads back to the bulkhead ll,while the corresponding forces on the collector tubes 32 of thecollector member 20 at the opposite end of the heat-exchanger are 6transmitted directly to the outer casing Why the 1313213931- and' dowels38-.

The end of the outer casing I0 enclosing the collector-assembly 2|; 21is constituted by a detachable cover 52, the. joint indicated at 53between which and the main body of the outer casing being formed bytongue andgroove elements and the cover 52 being secured by tie-bolts-54 whoseheads engage apertured lugs 55 extending inwardly from the wallof the main body of outer casing to and which carry external securingnuts 56.

Removal of the cover 52 gives access. to the collectors 2 lwhich areprovided. with detachable manhole covers lit-giving access to theirinsides- By undoing the for cleaning and like purposes. joints betweenthe collectors 21- and the header 21, removing the abutment nuts 50 andslacking off the tie-bolts 24 to release the clamps 26 from,the-marginal flanges 23 of the header plates H the collectors can beremoved bodily. This gives access to the tube-blocks it which can beextracted singly by lengthwise sliding after u-nscrewing the clampingnuts 41 from the studs 46.

This operation is facilitated by the. provision, of an external gantry(see Figure 8) consisting of a bridge structure 6| supporting an I-joist62, which extends longitudinally from the outer casing at a level abovethe tube-blocks and carries travelling slinging gear comprising atraveller 63 manually movable by means of a chain 64 and having. aslinging hook 65,. onv which isslung a yoke 66 carrying a pair ofrollers 61,. spaced apart at the correct distance to be engaged underthe flanges 3.9 of the tube-block M and take the weight of the latter asit isremoved by end-wise sliding fro-mthe support- 0f the rollers 4|mounted in the outer casing: 16.

The inlet opening it of theouter casing l0 communicates with a pair ofinlet trunks 69 i of a flexible joint (see Figures 5 to 7). The marginof the plate 58 is of angle section and presents a flange Ill facing themargin of opening it, while fixed to the outer casing I0 and surroundingthe opening 13 is an angle section coam-ing H, whose flange 12 faces andmates with the flange 10. A flexible sleeve 13 of graphited asbestosfabric (the seam of which (not shown) may be sewn or stapled) is slippedover the mating flanges 1c, 72 and secured thereto by metal clampingstrips 14 secured by bolts 15. At the corners the strips 14 are bentoutwards and the adjacent bent ends are secured together by bolts l'fi,a metal angle piece 11 being inserted at each corner to hold the fabricsleeve against the flange H! or 12.

The heat-exchanger described above is de signed for incorporation in astationary gas turbine for utilising exhaust heat to preheat the airleaving the compressor before entering the combustion chambers; Hotturbine-exhaust gas enters one compartment of the outer casing throughopening l3, circulates through the tubeblock casings l5 and is exhaustedfrom the other compartment of the outer casing, and it will be seen thatit cannot pass from one compartment to the other without passing throughthe tubeblock casings in close contact with the tubes l6, through whichair from the compressor, entering by way of the collector member 20,circulates in the opposite direction and is discharged through A thecollector assembly 2|, 2! to the combustion chambers, the heat-transferbeing recuperative.

We claim:

1. A multi-block tubular heat-exchanger comprising an outer casing, atransverse bulkhead having openings therein and dividing the interior ofthe casing into two compartments, one compartment having an inletopening and the other compartment having an outlet opening, a collectormember in each compartment extending outside the casing for admission offluid to one collector member and discharge of fluid from the othercollector member, said collector members having openings therein, anumber of closely spaced parallel tube-blocks, each comprising anopen-ended tubular casing inserted through one of the openings of thebulkhead and secured to the bulkhead in a substantially fluid-tightmanner, a bundle of closely spaced parallel tubes housed in saidopen-ended casing and extending beyond both open ends thereof, and aheader plate secured to the tube ends at each end of the tube-block, oneof said header plates being secured in a fluid-tight manner to thecollector member in one compartment of the casing so as to register withan opening thereof, a tubular cowl-like extension of the other headerplate registering with an opening of the other collector member, and afluid-tight expansion joint between the cowl-like extension and thelastnamed collectors member permitting movement of the cowl-likeextension relatively to the collector member in the axial direction ofthe tubeblock.

2. A tubular heat-exchanger as claimed in claim 1, in which eachtube-block casing has horizontal, longitudinal flanges, and the outercasing includes internal bracket structures and rollers mounted thereon,said rollers supporting the tube-blocks by engagement with theundersides of the horizontal flanges thereof.

3. A tubular heat-exchanger as claimed in claim 1, in which thetube-block casings have external flanges abutting on the margins of theopenings of the bulkhead and apertured bracket 8 structures extendingnormally from the flanges, and the bulkhead has studs extendingtherefrom through the apertures of the bracket structures, together withclamping nuts screwed on to the studs and engaging thebracket-structures for clamping the flanges to the bulkhead.

4. A tubular heat-exchanger as claimed in claim 3 including threadedtie-rods screwed into the clamping nuts, which are extended for thispurpose, apertured lugs extending from the collector member on the sameside of the bulkhead as the tie-rods, which extend through the aperturesof the lugs, and abutment nuts screwed onto the tie-rods and engagingthe lugs to resist the tendency of the internal pressure in thetube-blocks to move the collector member away from the bulkhead.

5. A form of construction of heat-exchanger as claimed in claim 1, inwhich there are at least two banks of vertically superposed tube-blocksand each collector member comprises at least two vertical branches and acommon header element interconnecting the branches at the top.

6. A form of construction of heat-exchanger as claimed in claim 1 inwhich the tube-blocks are of rectangular cross-section.

7. A form of construction of heat-exchanger as claimed in claim 1, inwhich the several tubelocks are similar and interchangeable. GEOFFREYBERTRAM ROBERT FEILDEN. RAYMOND ERNEST WIGG.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,639,225 Grace Aug. 16, 1927 1,696,435 Fraley Dec. 25, 19281,883,605 Davy Oct. 18, 1932 2,125,972 Wilson et al Aug. 9, 19382,269,619 Carpenter Jan. 13, 1942 2,285,651 Fischer June 9, 1942 FOREIGNPATENTS Number Country Date 228,297 Switzerland Nov. 1, 1943

